A 3'-Cluster is a negative DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 sequence discovered by Singh and coworkers, using a technique known as in vivo selection of an entire exon

In vivo selection of an entire exon

In vivo selection of an entire exon is a powerful technique used by Singh and coworkers to identify novel regulatory elements within an exonic sequence that undergoes alternative splicing. Thanks to in vivo, selection of the entire exon seven the of SMN gene, many regulatory elements have been...

.

The presence of 3'-Clusters prohibit the SMN2

SMN2

Survival of motor neuron 2, centromeric also known as SMN2 is a protein which in humans is encoded by the SMN2 gene.- Gene :This gene is part of a 500 kb inverted duplication on chromosome 5q13. This duplicated region contains at least four genes and repetitive elements which make it prone to...

 gene from producing its normal protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s which can lead to Spinal muscular atrophy

Spinal muscular atrophy

Spinal Muscular Atrophy is a neuromuscular disease characterized by degeneration of motor neurons, resulting in progressive muscular atrophy and weakness. The clinical spectrum of SMA ranges from early infant death to normal adult life with only mild weakness...

. 3'-Clusters in association with Exinct

Exinct

In genetics, exinct is a mutation. It was first described by Singh and coworkers to define a negative sequence within the coding region of SMN2 gene. Thanks to presence of Exinct, SMN2 gene is not able to produce the normal protein...

 have been observed to cause aberrant splicing of exon

Exon

An exon is a nucleic acid sequence that is represented in the mature form of an RNA molecule either after portions of a precursor RNA have been removed by cis-splicing or when two or more precursor RNA molecules have been ligated by trans-splicing. The mature RNA molecule can be a messenger RNA...

7, leading to the production of a short SMN transcript that makes a truncated non-functional SMN protein. Another regulatory element ISS-N1 has been also found to affect the aberrant splicing of exon 7.